Thermostatic switch



Dec. 16, 1941. N R M ART 2,266,158

THERMOSTATIC SWITCH Filed July 3, 1940 #790177 END 0! CAR REAR END 0''CAR [jazz [a 27% HlIIII- /0 Z9 Inventor /VOBL 6. BR UMG/IRT By fimaoiizm Attorney Fireman. 16, 1941 UNITED STATES-PATENT OFFICE 2,266,158rnamos'm'rrc s wrrcn Noble G; nru'mga'rt, mam, 111.

Application 1111! a, 1940, Serial No. 343,856 1 Claim. (Ct-211F137) Thepresent invention relates to new and useful improvements in switches andmore particu larly to a thermostatic switch adapted to be used inconjunction with the journal-boxes of railway rolling stock with theprincipal object in view to warn trainmen of "hot boxes as they occur byproper indication inside of the rolling stock.

Another object of the invention is to provide a switch of the characterstated which can be installed in the journal boxes of railway rollingstock without any likelihood of the same interfering with the properfunctioning of the box.

Still another important object of the-invention is to provide a switchof the character stated which will be positive acting and notsusceptible to the ready development of defects. I

In the drawing:

Figure 1 represents a side elevational view of the switch shown inupright position and mounted in a journal box.

Figure 2 is a vertical sectional view taken substantially omthe'line 2-2of Figure 1.

Figure 3 is a horizontal sectional view on the line 3,-! of Figure 2.

Figure 4 is a top plan view of the switch.

Figure 5 is a diagrammatic view disclosing the electrical connectionsbetween the electrical devices involved.

e Referring to the drawing wherein like numerals de i ate like parts, itcan be seen that A generally refers to a railroad rolling stock journalbox, while B generally refers to the thermostatic switch, the upper endof which is disposed through the top of the journal box and held bysuitable brackets3-3. Thus the switch is held in a vertical positionwith the thermostatic elementthereof, immediately opposed to thecorrespending" journal. Numeral 5 denotes an elongated trough-likestructure preferably ofqarass or other metal having the side walls 8,bottom wall 1, end walls 8 and 9. Disposed in this troughlike structure,which is open on one side is the thermostatic element generally referredto by numeral ID. This thermostatic element consists of a plurality ofU-shaped elements, the present invention as illustrated being disclosedwith three of these U-shaped elements, the intermediate element havingthe end of its leg portion connected to the end portions of the opposedlegs of the adjacent U-shaped element. Obviously, more than three ofthese U-shaped elements may be employed if seen fit. Obviously, thisthermostatic unit ID will expand under heat, in the trough-likestructure 5.

' One end leg of the unit It bolt ll having .a nut l2, extending througha threaded bushing II in the bottom wall 9. The other end leg of theunit Ill, normally bears against the push rod ll which is slidably disisconnected by a posed through a guide structure or protuberance in theupper wall [defining a threaded nipple IS.

The outer end of this push rod I has the bridge member i6 thereon and acoiled spring I! is located on this rod l4 between the upper end leg ofthe thermostaticunit and the aforementioned nipple l5 for the purpose ofmaintaining the rod urged downwardly and against the said leg at theupper end of the thermostatic unit. In this manner, the bridge member I6is held spaced from the contacts l8 which are located on pins l8extending through bushings 20 of insulation in the end wall 2! of a cap22, which is threadedly engaged over the nipple I5.

Obviously, this switch can be mounted in any suitable manner in apacking box, or in face elsewhere and a socket type plug can be engagedover the prongs IQ for connecting the switch with a source of current 23and suitable indicating lamps 24, which, of course, can be annunciatorsif desired and in the case of rolling stock, for indicating hot boxes,there will preferably be two of these lamps 24 at each end of a car andperhaps one for each journal box.

Obviously, when the thermostatic element I0 .expands under undue heatingconditions, the

what is bottom wall and end walls, one end wall provided with aremovable plug therein, the other end wall being provided with athreaded extension, an internally threaded cap for disposition over theextension, a contact in the cap, said extension and adjacent end wall ofthe trough-like structure being formed with a bore, a push rod slidablydisposed through the bore and having a head engageable with the contactwhen forced in-the direction of the cap, a longitudinally expansiblethermostatic element disposed in the trough-like structure and havingone end attached to the plug, said plug being adjustably disposed in itsend wall, and spring means on the push rod normally tending to urge thepush rod against the adjacent end of the thermostatic element.

NOBLE G. BRUMGART.

